Bit holder for cutter chains



Sept. 29, 1942. A. R. LONG ET AL 1 2,297,570

R CHA OLDE File 2 S FIG. E.

7 j 03w I Fl Sept. 29, 1942. A. R. LONG ET AL 2,297,570

BIT HOLDER FOR CUTTER CHAINS Filed March a, 1941, 2 Sheets-Sheet 2 Armistaad R..Lpn John ELLEN-Lg.

ATTORNEYS.

INVENTORS.

Patented Sept. 29, 1942 F ICE BIT HOLDER FOR. CUTTER CHAINS Armistead R. Long and JohnB. Long, Fayetteville, W. Va.

Application March 8, 1941, Serial No. 382,422

8 Claims.

The present invention relates broadly to cutter chains for coal mining machines and more particularly to improvements in cutter bits together with holders for securing the bits in working position in cutter chain bit blocks.

The primary object of the invention is to provide an improved bit holder for cutter chains such as will eliminate breaking or damaging of the inactive cutting point of reversible dual or double pointed bits when the holder is clamped in the chain block.

Cutter chains of coal mining machines are provided with links forming bit blocks which have sockets for receiving the shanks of bit holders, the holders being usually secured in the block by means of a set screw acting against a side of the shank. In some cutter chains these holders are adapted to receive reversible double pointed triangular shaped bits which are so received in the holder that one inactive end of the bit extends into the socket in the bit block with a wall of the :bit projecting slightly beyond the rear wall of the shank of the holder. When the set screw is tightened against the front wall of the shank,

the entire pressure is upon the projecting wall of It is therefore a further object of the invention to provide an improved bit holder for cutter chains wherein the inactive cutting point of the bit is relieved of any clamping pressure and thus eliminating possibility of the cutting point being broken due to set screw pressure or other clamping action.

A further object of the invention is to provide an improved bit holder which will not only prevent the inactive cutting point of the dual bit from breaking, but also serves for more securely holding the holder in the chain block.

A further object is to so construct the holder and bit that when secured in the chain block the pressure will be upon the inner end of the shank of the holder and upon the heavier medial portion of the bit, with the inactive cutting point of the bit free from contact with the chain block.

A further object resides in the means for bracing the bit and securely locking the bit in the holder without interfering with the bit clearance or creating undue drag during cutting.

A further object is to provide an improved bit holder for cutter chains which is adapted to receive two like shaped double pointed bits providing four cutting points available for use, with one of the bits forming a key bit when the other bit is disposed in operative cutting. position;

A still further object resides in the novel formation of the holder and bit, providing for strength and ease of construction, as well as better seating of the bit in the holder. Y

A still further objectresides in the specific formation of the bit, together with the'manner in which the bits may be economically formed from bar material. I l I l 7 Other objects and'advantages of the invention will be apparent from the following detailed description taken in connectionv with the accompanying drawings forming'a part of this specification and in which drawings. v

Figure lis aside view of a cutter chain block with the upper portion ofthe block in longitudinal section and showing one form of the improved bit holder in position in the block, the holder being shown in section. 7 7

Figure 2 is a section substantially on line 2-2 of Figure 1.'

Figure 3 is an end view of the outer end of the holder with a cutting bit in place.

Figure 4 is a perspective view of the holder shown in Figures 1 to 3.

Figure 5 is a perspective view of the cutting bit.

Figure 6is a fragmentary longitudinal section thru a chain block and showing a modified form of the invention, the outer portion of the holder being in section.

Figure 7 is a top view of the showing in Figure 6.

Figure 8 is a section on line 88 of Figure 6.

Figure 9 is a transverse section thru the holder on the line 9-9 of Figure 6, but with the bits omitted.

Figure 10 is a perspective view of the holder shown in Figure .6.

Figure 11 is a section thru the outer end or head portion of the holder shown in Figure 6.

Figure 12 is a view showing the manner in which the cutter bits may be cut from a length of bar material.

In the drawings, like reference characters designate corresponding parts thruout the several views.

Referring first to the form of the invention shown in Figures 1 to 5 inclusive, the letter A may designate an ordinary cutter chain and B a chain block forming a link in the chain and adapted to receive a cutter designated as a whole by the letter C.

The chain block B may be of standard or usual construction and is provided with a socket of rectangular shape in cross section and opening at the outer end face 6 of the block. Threaded thru the forward portion of the block is a set screw 1 which extends thru the forward wall of the socket 5 and serves to removably secure the cutter C in operative position in the chain block.

The improved cutter C comprises a bit holder 8 having a removable and reversible cutting bit H) which is held in operative cutting position in the holder when the holderis secured in position in the socket 5 of the chain block B. v

The holder 8 may be cast from suitable steel and includes a shank H which may be rectangular shape in cross section forming a rear side or'face l2 for confronting the rear wall l3 of the socket 5. Formed on the outer end of the shank is a head M which extends rearwardly beyond the rear side |2 of the shank and forms a heel or bearing portion l4 adapted to bear upon the outer face 5 of the chain block and acts to resist bending strain on the-shank The head I4 is relatively narrow and of slightly greater width at its lower portion than the width of the socket 5, providing shoulders along each side of the shank for engaging the outer face' 5 of the chain block as shown in Figure 2. The sides and end surfaces of the head I4 generally taper toward the top or outer end of the head, with the forward end of the head having a relatively flat, slightly rearwardly inclined face |6 which as shown in Figures 2 and 4 tapers toward the outer end of the head. Formed at the extreme outer end of the head is a retaining and bracing rib I! which extends longitudinally of the head as shown. Extending rearwardly from the inner end of the shank beyond the rear side l2 of the shank, is a bearing or spacing lug l5 which is adapted to engage the rear wall |3 of the socket 5 and space the wall l2 of the shank from the wall |3. The forward edge of the shank I may be recessed slightly as at |8 forming a seat for the set screw 1.

The holder 8 is-provided with an-upwardly tapering bit receiving aperture or way providing upwardly converging faces 2| and 22 whereby the smaller upper end of the aperture opens thru the head l4 beneath the forward end of the rib H. The lower end of the face -2| terminates in the rear side I2 of the shank H in spaced relation above the lug l5, while the lower end of the face 22 terminates in the rear or heel portion M of the head l4, rearward of the shank The face 2|, as shown in Figure 4, is transversely rounded or concaved thruout its length for a purpose to be later described.

The cutting bit I0 is of triangular shape having the form of an isosceles triangle providing a base side or edge 24 and equilateral sides or legs 25 and 26 forming opposed cutting points or ends 21 and 28 at the opposite ends of the bit. As shown in Figure 12, the cutting bits l0 may be formed by cutting the bits from round'edge flat bar stock 29, by diagonally cutting the bar along the dot and dash lines as shown. By so cutting the bits from round edge flat bar stock, the sides 25 and 26 of the bit will be fiat, while the longer side 24 will be rounded or transversely convex thruout its length whereby the cutting ends 21 and 28 will have an arcuate cutting edge and be somewhat pointed as is clearly shown in Figures 2, 3 and 5. The angle of the sides 25 and 26to the base '24 of the bit coincides with the angular relation of the 'upwardlyco'nverging edges 2| and 22 of the bit aperture 20, with the altitude of the bit beinggreater than the Widthbfthe upper smaller end of the aperture. Thus, when the bit IE! is fitted in the aperture 20 as in Figure 2 with its longer edge 24 engaging the face 2| and its side 25 engaging the face 22 of the aperture, one cutting point, as the point 27, will project from the upper end of the aperture into active cutting position, while the cutting point 28 will project slightly beyond the rear side l2 of the shank H and with the side 26 of the bit in a slight upward 1y divergent relation to the rear side of the shank With the bit Hi seated in the aperture 20, the shank H of the holder 8 may be inserted in the socket 5 so that when pressure is brought upon the shank by the set screw 1, the lug |5 at the inner end of the shank will be forced into contact with the rear wall l3 of the socket, and the heavier intermediate portion of the bit into contact with the outer end of the wall I3, so that the inactive cutting point 28 of the bit is free of any contact with'the chain block. Thus, when the set screw 1 is tightened, the bit is forced upward in the wedge-like aperture 20 and the lug 5 forms one of "the bearing points, while the heavier intermediate portion of the bit forms another bearing point for the set screw pressure. Since no pressure is upon the inactive cutting point 28, the point is prevented from becoming broken or damaged by the set screw pressure. When the active cutting point becomes worn or broken thru use, the bit may be readily reversed in the holder for presenting a new cutting point in cutting position.

By having the face 2| of the aperture 2|] transversely concaved, and the cutting bit formed from round edge flat bar material, provides a better fit in that the convex edge of the bit will seat solidly in the concave face 2| and eliminate any side play such as may cause bending. The holder may also'be more easily cast and cleaned by filing, and the rounded edges of the face 2| provide the'proper fillets which add materially to the strength of the holder and lessens the likelihood of faulty castings due to shrinkage cracks at sharp corners,

The retaining or bracing rib I! along the outer end of the head' M of the holder is of a width no greater than the thickness of the cutting bit ID and has its forward portion extending in overhanging relation to the outer end of the bit aperture 20; The rib ll forms a brace for the active or working'end' of the bit, and being no wider than the bit does not interfere with the bits clearance nor create any drag during cutting. The overhanging "or" protruding forward 'end of the rib also'serves to more securely lock the bit in place thru providing a longer bearing surface for'the bit edge 25, and prevents the bit from coming out should'the holder become worn.

The relatively fiat, slightly rearwardly inclined face H5 at the forward end of the head M, having its upper end terminating below the upper open end of the aperture 20, acts to eii iciently clean and drag the coal cuttings out of the out, whereas a rounded forward end on the-head tends to grind'up the cuttings and not drag them out of thecut.'

Referring now to the form of the invention shownin Figures 6 to 11 inclusive, the letter B designates a chain block of a cutter chain and-D a cutter adapted to be held in the block B.

The chain block'B' is similar to that shown in Figure land is provided with a rectangular shaped socket 5' opening at the outer end face 6"of the block-1* Aset'screw "|'-is threaded thru the forward portion of the chain block and extends thru the front wall of the socket for securing the cutter D in operative cutting position in the chain block.

The cutter D comprises a bit holder which is adapted to hold two similar cutting bits 3| and 32 which are interchangeable end for end and with each other to provide a total of four cutting points available for use. When one bit is an active or cutting position, the companion bit is inactive and serves as a key or keeper for the active bit. In the example illustrated, and for purpose of explanation, the bit 3| is shown in cutting or active position while the bit 32 forms the inactive or key bit.

The bit holder 39 is cast from suitable metal and embodies a rectangular shaped shank 33 formed at its outer end with a head 34 which extends rearwardly beyond the rear side or face 35 of the shank and provides a bearing portion adated to bear upon the outer face 5 of the chain block. The head 34 is tapered generally toward the outer end of the head and at its forward end has a relatively fiat, slightly rearwardly inclined face 36 having its side edges tapering toward the outer end of the head. Projecting rearwardly from the inner end of the shank 33 is a spacing lug or boss 3'! which is adapted to bear against the rear wall 38 of the socket 5 and space the rear wall 35 of the shank from the rear socket wall 33. The forward edge of the shank 33 is recessed as at 39 forming a seat for the set screw 1'.

The holder is formed with an upwardly and forwardly inclined tapering key bit aperture 4|! opening at its upper end thru the forward portion of the head 34 and providing upwardly converging faces and 42. The lower .end of the face 4| terminates in the rear side 35 of the shank 33, while the lower end of the wall 42 terminates in the lower face of the head rearward of the shank 33. The faces 4| and 42 are transversely rounded or concaved thruout their length as clearly shown in Fig. 9. A tapered second or cutting bit aperture 43 is formed thru the head 34 with the smaller rear end of this aperture opening thru the rear of the head and the forward end of the aperture 43 intersecting the upper end of the aperture to form a single opening at the forward side of the head. The aperture 43 provides rearwardly converging faces 44 and 45, the former of which is transversely rounded and opens at its forward end above the upper end of the wall 4|, while the wall 45 intersects the upper end of the wall 42 rearwardly of the opening 46. The taper of the walls of the recess 43 coincides with the taper of the walls of the recess 43.

The bits 3| and 32 are of like construction and interchangeable so that when either one of the bits is disposed in cutting position in the aperture 43, the companion bit may be placed in the aperture 43 as the inactive bit and form a keeper or key bit for the cutting bit. The triangular bits 3| and 32 are of isosceles form, each provided with a base side or edge 4'! and equilateral sides or legs 48 and 49 forming opposed cutting points or ends 50 and 5| at the ends of the bit. The altitude of the bits 3| and 32 is no greater than the height of the opening 46 and when a bit is inserted in cutting position in the aperture 43 the vertex of the bit is disposed inwardly of the mouth of the opening so that a portion of the key bit in the aperture 40 projects thru the opening 48 in supporting contact with the active end of the cutting bit. The transversely convex edge of the bit 3| engages the concaved edge 44 of the aperture 43, while the transversely convex edge of the bit 32 engages the concaved edge 4| of the aperture 40.

When the cutting bit 3| is inserted into the aperture 43 with its longer edge 41 engaging the face 44 and its side 49 engaging the face 45 of the aperture, the cutting point 50 projects forwardly from the head 34 while the cutting point 5| projects rearwardly from the head. The key or keeper acting bit 32 is then inserted into the aperture 4|) with its longer edge 41 engaging the face 4| of the aperture 4!] and its cutting point 3| projecting slightly beyond the rear side 35 of the shank 33 with the side 49 of this bit 32 in slight upwardly diverging relation to the rear side 35 of the shank. The upper end of the bit extends a short distance beyond the opening 46 with the side 48 of this bit engaging the side 48 of the active bit 3|. Thus the bit 32 serves to retain the bit 3| in place in the aperture 43.

When the bits 3| and 32 are assembled in the holder 34, the shank 33 is inserted in the socket 5 of the chain block B. When the set screw 7' is tightened against the front edge of the shank 33, the lug 31 at the inner end of the shank will contact the rear wall 38 of the socket, while the heavier intermediate portion of the bit 32 will contact the outer end of the wall 38 thus leaving the cutting point 5| of the inactive or keeper bit 32 free of any pressure. Since the bits 3| and 32 are duplicates, the bits may be reversed end for end and interchanged so as to provide four cutting points which may be disposed in active cutting position,

Thus in both forms of the invention an inactive cutting point, of the bit is prevented from becoming broken or damaged by the clamping pressure of the set screw, thru spacing the inactive cutting point from contact with either the chain block or the shank of the bit holder. As will be seen in each of Figures 1 and 6, the sides 23 and 49 of the bits It and 32 respectively, are in upwardly converging relation to the rear wall of the chain block socket.

Changes in detail may be made to the forms of the invention herein shown and described without departing from the spirit of the invention or the scope of the following claims.

We claim:

1. In a cutter chain, a chain block having a socket including a rear wall, a bit holder having a shank fitting in the socket, a bit receiving aperture in the holder and opening at one end thru the rear side of the shank, a double pointed bit fitting in the aperture and having its inactive cutting point protruding from the rear side of the shank, a lug projecting from the rear side of the shank at the inner end of the shank, and means for clamping the'shank in the socket whereby said lug will contact the rear wall of the socket, and the bit, at a location spaced from its inactive cutting point will also contact the said rear wall with said inactive cutting point free of contact with both the shank and the chain block.

2. In a cutter chain, a chain block having a socket including a rear wall, a bit holder having a shank fitting in the socket, a lug on the inner end of the rear side of the shank, a tapering aperture in the holder and opening at its larger end thru the rear side of the shank, a triangular shaped fit fitting in the aperture with one of its sides extending into the socket rearwardly of said shank and in upwardly converging relation to the rear wall of the socket, and a set screw for clamping the shankin the socket with said lug and the intermediate portion of the bit in bearing contact with the rear socket wall.

'3. A cutter for cutter chains, comprising a holder including a head and a shank having a rear wall, a lug at the end of said rear wall remote from said head, and a triangular shaped bit of isosceles form received in the holder with one of the equal sides of the bit rearwardly of and located in a plane in angular relation to the lane of the rear side of said shank, said planes divergingin a direction from said lug toward said head.

4. In a cutter chain, a chain block having a socket, a holder including a shank fitting in the socket and a head at the outer end of the shank, a lug on the inner end of the shank engageable with the rear wall of the socket, an upwardly tapering key aperture opening at its upper end thru the head, a rearwardly tapering bit aperture opening at its rear end thru the head and at its forward end intersecting the key aperture, and a cutter bit fitting in each apertur with the ends of the bits extending beyond the ends of the apertures, said bits being similar and interchangeable in th apertures whereby one bit forms a keeper for the companion bit, said bits when forming a keeper bit having the intermediate portion of the bit engageable with the rear wall of said socket.

5. In a cutter chain, a chain block having a socket, a holder including a shank adapted to be clamped in the socket, a key aperture and a bit aperture in the holder, said apertures opening in a single opening in the holder, and a double pointed cutter bit received in each aperture, said bits being reversible in the apertures and interchangeabl one for the other whereby when one bit is in a cutting position in the bit aperture the bit in the key aperture forms a keeper for the cutting bit.

6. In a cutter for cutter chains, a holder including a shank and a head at the outer end of the shank, a spacer lug at the rear inner end of the shank, an upwardly and forwardly tapering key aperture opening in the forward side of the head, a rearwardly tapering bit aperture extending thru the head and at its forward end communicating with the upper end of the key aperture, and a triangular shaped bit received in each aperture, said bits being similar and interchangeable so that a bit when in the key aperture engages and forms a keeper for the bit in cutting position in the bit aperture, a bitwhen in the key aperture having a portion extending rearward of the holder shank.

'7. A cutter for cutter chains comprising a holder including a head provided with an upwardly and forwardly inclined tapering aperture open to the upper end portion of the head, the forward wall of the aperture being transversely concaved, and a bit provided with converging sides fitting in said aperture, the leading side of the bit being concaved transversely to fit said concave wall of the aperture in the head and presenting a leading convex face to the work.

8. In combination with a cutter chain block having a socket, a holder including a shank received in the block socket and a head at the outer end of the shank, said head relatively narrow and of greater width than said socket providing shoulders along each side engaging the outer face of the block, the sides of the head tapering toward the top of the head, and the leading end of the head having a flat face rearwardly inclined from the block toward the top of the head, with a bit receiving aperture opening thru the head above said leading inclined face, and a cutter bit in said aperture and projecting from the said opening thereof above said leading inclined face.

ARMISTEAD R. LONG. JOHN B. LONG. 

